Influence of restraints on body-casted child ATDs in front and side sled tests

The current study was designed to study hip spica casted and uncasted child dummies in front- and side-impact tests using a variety of restraints.

Casted one- and three-year-old ATDs were restrained by a traditional child seat, a special hip spica child seat, and the vehicle seat belts. All tests positioned the child upright in either the rear-facing (one-year-old) or forward-facing (three-year-old) direction. One exception was vehicle seat belt tests for the one-year-old, which required the child to be positioned supine due to the position of the child's body imposed by the cast. The ATDs were tested in frontal impacts per FMVSS 213 (delta V of 30 mph) and in side impact using the pulse proposed for 213 (delta V of 20 mph). Corresponding control tests were performed with the uncasted ATDs. The FMVSS 213 mandated injury metrics (HIC36, 3 ms chest gs) and nonmandated due care metrics (HIC15, Nij) were evaluated.

For the one-year-old casted tests, 50 percent of the responses increased when compared to the uncasted control. A similar comparison for the three-year-old revealed an 80 percent increase when the dummy was fit with a body cast. HIC36 and chest gs were below the limits established in FMVSS 213 for all casted and uncasted tests. Frontal peak Nij values were in the tension-extension in nine out of ten cases and ranged from 0.8 to 0.83 (uncasted) and 1.02 to 1.92 (casted). Side-impact Nij was approximately 50 percent of the corresponding frontal tests.

The addition of a body cast increases head, neck, and chest responses in front- and side-impact tests. The increases are greatest for the three-year-old who was forward facing.